This invention relates to a method of and apparatus for quantitatively and qualitatively determining the dust content released during opening of fibrous material, especially cotton, and especially fibrous material to be used in an open-end spinning process.
In an open-end spinning process, the dust content of the fibrous material plays a particular part, and in fact a decisive part in the carrying out of the open-end process. As is known, the opening of the fibrous material into individual fibers on the rotor releases fine dust, which reduces the yarn quality by blocking the collecting surface of the rotary spinning chamber, and can even lead to yarn breakage, or production loss resulting from cleaning operations.
In processing fibrous material it is of great importance to know the dust content of the sliver fed to the open-end spinning unit, and whether or not the sliver is suitable for spinning by an open-end process. Test apparatus used in conventional ring spinning processes, in which the fine dust content of the sliver does not play the same part as in an open-end process, is insufficient for an open-end process, as such apparatus separates only coarse dust and fibers. With the usual test apparatus, dust particles down to a granular size of 3 to 5 micrometers are accessible for measurement, whereas in fine dust which settles on the collecting surface of the rotary spinning chamber, there may be dust particles of 0.2 micrometers and less. A considerable part of the fine dust which causes production difficulties in an open-end spinning process is not caught by the previous test method, and these measurement results cannot be used successfully for an open-end spinning process.
Hitherto open-end spinning generally proceeded from the testing of a specific type of cotton on an open-end spinning unit to determine whether the spinning proceeds satisfactorily. This merely enabled it to be ascertained whether the particular type of cotton was suitable for the open-end spinning unit. No prediction was obtained regarding the quantitative and qualitative proportion of the dust. In addition, carrying out these tests on a production unit led in part to increased costs due to loss of time and production output.